9
-1
Section::::Abstract.
Number
21690
9
-1
Section::::Abstract.
Sudoku
1365807
nine
-1
Section::::Main classification.:Real numbers.

Number
21690
nine
-1
Section::::Abstract.
Sudoku
1365807
Nine
-1
Section::::History.:Negative numbers.

Number
21690
Nine
-1
Section::::History.:Spread outside Japan.

Sudoku
1365807